164 research outputs found

    EuropÀische Integration aus historischer Erfahrung, Ein ZeitzeugengesprÀch mit Michael Gehler = European integration from a historical experience, A Discussion with Michael Gehler. ZEI Discussion Paper C227, 2015

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    From 1995 to 1999 Monika Wulf-Mathies served as EU commissioner responsible for regional and cohesion policy. She tells us the story of the EU Commission under President Jacques Santer with regard to the historical development of the preparation of the Economic and Monetary Union (EMU), the Union Treaty of Amsterdam (1999) and the EU-Eastern Enlargement. She touches also controversial aspects of the Santer Commission, which led to her collective demission in 1999. According to Wulf-Mathies the increase of EU's democracy deficit is result of an erosion process of the common institutions caused by the nation states which contributed to their weakness. The democratic substance of the union suffers because of the 'summarization' of the EU decision making processes. Monika Wulf-Mathies argues in favor of the community method, which needs revitalization. She proposes European democracy enforcement and transfers of the national budget und economy policies to EU bodies. This eyewitness talk offers an actual EU analysis as well as an assessment of the Santer Commission

    Neighbours of arbuscular‐mycorrhiza associating trees are colonized more extensively by arbuscular mycorrhizal fungi than their conspecifics in ectomycorrhiza dominated stands

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    Arbuscular mycorrhiza represents a ubiquitous nutritional symbiosis between the roots of most terrestrial plant species and fungi of the subphylum Glomeromycotina (Spatafora et al., 2016). Terrestrial habitats are unlikely to be limited in propagules of arbuscular mycorrhizal fungi (AMF), because AMF propagule densities build up fast in vegetated soil (e.g. Gould et al., 1996). We start to appreciate, however, that shortages in AMF propagules are common in some habitats, such as agricultural ïŹelds subject to intensive farming (Schnoor et al., 2011; Manoharan et al., 2017). Forest habitats in the temperate region might also be occasionally AMF propagule limited (Veresoglou et al., 2017), but to the best of our understanding this has not been shown with empirical data

    Managing Visibility and Validity of Distress Calls with an Ad-Hoc SOS System

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    The availability of ICT services can be severely disrupted in the aftermath of disasters. Ad-hoc assemblages of communication technology have the potential to bridge such breakdowns. This article investigates the use of an ad-hoc system for sending SOS signals in a large-scale exercise that simulated a terrorist attack. In this context, we found that the sensitivity that was introduced by the adversarial nature of the situation posed unexpected challenges for our approach, as giving away one's location in the immediate danger of a terrorist attack became an issue both for first responders and the affected people in the area. We show how practices of calling for help and reacting to help calls can be affected by such a system and affect the management of the visibility and validity of SOS calls, implying a need for further negotiation in situations where communication is sensitive and technically restrained

    Hedging against biodiversity loss : forest herbs’ performance in hedgerows across temperate Europe

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    Questions: How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along these linear habitats? Location: Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome. Methods: First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional life‐history traits for four forest herbs (Anemone nemorosa, Ficaria verna, Geum urbanum, Poa nemoralis) with contrasting flowering phenology and colonisation capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats. Results: All study species showed a higher above‐ground biomass in hedgerows than in forests. For Poa nemoralis and Geum urbanum, we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher sub‐canopy temperatures therein. The “ancient forest herb” Anemone nemorosa, however, appeared to have a lower reproductive output in hedgerows than in forests, while for Ficaria verna no reproductive differences were found between the two habitats. Conclusions: This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to the long‐term conservation and migration of forest herbs in the face of global environmental change

    Seasonal drivers of understorey temperature buffering in temperate deciduous forests across Europe.

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    Aim:Forest understorey microclimates are often buffered against extreme heat or cold, with important implications for the organisms living in these environments. We quantified seasonal effects of understorey microclimate predictors describing canopy structure, canopy composition and topography (i.e., local factors) and the forest patch size and distance to the coast (i.e., landscape factors). Location:Temperate forests in Europe. Time period:2017-2018. Major taxa studied:Woody plants. Methods:We combined data from a microclimate sensor network with weather-station records to calculate the difference, or offset, between temperatures measured inside and outside forests. We used regression analysis to study the effects of local and landscape factors on the seasonal offset of minimum, mean and maximum temperatures. Results:The maximum temperature during the summer was on average cooler by 2.1 °C inside than outside forests, and the minimum temperatures during the winter and spring were 0.4 and 0.9 °C warmer. The local canopy cover was a strong nonlinear driver of the maximum temperature offset during summer, and we found increased cooling beneath tree species that cast the deepest shade. Seasonal offsets of minimum temperature were mainly regulated by landscape and topographic features, such as the distance to the coast and topographic position. Main conclusions:Forest organisms experience less severe temperature extremes than suggested by currently available macroclimate data; therefore, climate-species relationships and the responses of species to anthropogenic global warming cannot be modelled accurately in forests using macroclimate data alone. Changes in canopy cover and composition will strongly modulate the warming of maximum temperatures in forest understories, with important implications for understanding the responses of forest biodiversity and functioning to the combined threats of land-use change and climate change. Our predictive models are generally applicable across lowland temperate deciduous forests, providing ecologically important microclimate data for forest understories

    The History of Science and Current Perspectives in Dialogue

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    Research on urban space has a long tradition in classical studies. Current research of ancient urban spaces continues on in this tradition. It is essential to determine the position of research history in order to define the prospects of current urban studies in a more dif- ferentiated way: only those who are conversant with the history-of-science determination of their respective fields are able, intuitively and critically, to put innovative approaches and methods to the test. Based on the projects of the research group C-6, the various threads of history-of-science developments will be outlined and the current approaches defined in the context of constant re- orientation and new orientation of classical urban studie

    Strength of forest edge effects on litter-dwelling macro-arthropods across Europe is influenced by forest age and edge properties

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    International audienceAim: Forests are highly fragmented across Western Europe, making forest edges im ‐portant features in many agricultural landscapes. Forest edges are subject to strong abiotic gradients altering the forest environment and resulting in strong biotic gradi ‐ents. This has the potential to change the forest's capacity to provide multiple eco ‐system services such as nutrient cycling, carbon sequestration and natural pest control. Soil organisms play a key role in this perspective; however, these taxa are rarely considered in forest edge research.Location: A latitudinal gradient of 2,000 km across Western Europe.Methods: We sampled six dominant taxa of litter‐dwelling macro‐arthropods (car ‐abid beetles, spiders, harvestmen, centipedes, millipedes and woodlice) in forest edges and interiors of 192 forest fragments in 12 agricultural landscapes. We related their abundance and community composition to distance from the edge and the inter ‐action with forest age, edge orientation and edge contrast (contrast between land use types at either side of the edge).Results: Three out of six macro‐arthropod taxa have higher activity‐density in forest edges compared to forest interiors. The abundance patterns along forest edge‐to‐in‐terior gradients interacted with forest age. Forest age and edge orientation also influ ‐enced within‐fragment compositional variation along the forest edge‐to‐interior gradient. Edge contrast influenced abundance gradients of generalist predators. In general, older forest fragments, south‐oriented edges and edges along structurally more continuous land use (lower contrast between forest and adjacent land use) re ‐sulted in stronger edge‐to‐interior gradients while recent forests, north‐oriented edges and sharp land use edges induced similarity between forest edge and interior along the forest edge‐to‐interior gradients in terms of species activity‐density and composition.Main conclusions: Edge effects on litter‐dwelling macro‐arthropods are anticipated to feedback on important ecosystem services such as nutrient cycling, carbon se ‐questration and natural pest control from small forest fragments

    Responses of competitive understorey species to spatial environmental gradients inaccurately explain temporal changes

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    Understorey plant communities play a key role in the functioning of forest ecosystems. Under favourable environmental conditions, competitive understorey species may develop high abundances and influence important ecosystem processes such as tree regeneration. Thus, understanding and predicting the response of competitive understorey species as a function of changing environmental conditions is important for forest managers. In the absence of sufficient temporal data to quantify actual vegetation changes, space-for-time (SFT) substitution is often used, i.e. studies that use environmental gradients across space to infer vegetation responses to environmental change over time. Here we assess the validity of such SFT approaches and analysed 36 resurvey studies from ancient forests with low levels of recent disturbances across temperate Europe to assess how six competitive understorey plant species respond to gradients of overstorey cover, soil conditions, atmospheric N deposition and climatic conditions over space and time. The combination of historical and contemporary surveys allows (i) to test if observed contemporary patterns across space are consistent at the time of the historical survey, and, crucially, (ii) to assess whether changes in abundance over time given recorded environmental change match expectations from patterns recorded along environmental gradients in space. We found consistent spatial relationships at the two periods: local variation in soil variables and overstorey cover were the best predictors of individual species’ cover while interregional variation in coarse-scale variables, i.e. N deposition and climate, was less important. However, we found that our SFT approach could not accurately explain the large variation in abundance changes over time. We thus recommend to be cautious when using SFT substitution to infer species responses to temporal changes.</p

    High ecosystem service delivery potential of small woodlands in agricultural landscapes

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    Global forest loss and fragmentation have strongly increased the frequency of forest patches smaller than a few hectares. Little is known about the biodiversity and ecosystem service supply potential of such small woodlands in comparison to larger forests. As it is widely recognized that high biodiversity levels increase ecosystem functionality and the delivery of multiple ecosystem services, small, isolated woodlands are expected to have a lower potential for ecosystem service delivery than large forests hosting more species. We collected data on the diversity of six taxonomic groups covering invertebrates, plants and fungi, and on the supply potential of five ecosystem services and one disservice within 224 woodlands distributed across temperate Europe. We related their ability to simultaneously provide multiple ecosystem services (multiservice delivery potential) at different performance levels to biodiversity of all studied taxonomic groups (multidiversity), forest patch size and age, as well as habitat availability and connectivity within the landscape, while accounting for macroclimate, soil properties and forest structure. Unexpectedly, despite their lower multidiversity, smaller woodlands had the potential to deliver multiple services at higher performance levels per area than larger woodlands of similar age, probably due to positive edge effects on the supply potential of several ecosystem services. Biodiversity only affected multiservice delivery potential at a low performance level as well as some individual ecosystem services. The importance of other drivers of ecosystem service supply potential by small woodlands in agricultural landscapes also depended on the level of performance and varied with the individual ecosystem service considered. Synthesis and applications. Large, ancient woodlands host high levels of biodiversity and can therefore deliver a number of ecosystem services. In contrast, smaller woodlands in agricultural landscapes, especially ancient woodlands, have a higher potential to deliver multiple ecosystem services on a per area basis. Despite their important contribution to agricultural landscape multifunctionality, small woodlands are not currently considered by public policies. There is thus an urgent need for targeted policy instruments to ensure their adequate management and future conservation in order to either achieve multiservice delivery at high levels or to maximize the delivery of specific ecosystem services
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